<?php
namespace App\Third;
use App\Third\PKCS7Encoder;
use App\Third\ErrorCode;
use App\Third\Prpcrypt;
use App\Third\SHA1;
use Log;
use DOMDocument;
/**
 * 对微信小程序用户加密数据的解密示例代码.
 *
 * @copyright Copyright (c) 1998-2014 Tencent Inc.
 */
class WXBizMsgCrypt
{
    private $m_sToken;
    private $m_sEncodingAesKey;
    private $m_sCorpid;

    /**
     * 构造函数
     * @param $token string 公众平台上，开发者设置的token
     * @param $encodingAesKey string 公众平台上，开发者设置的EncodingAESKey
     * @param $Corpid string 公众平台的Corpid
     */
    public function __construct($token, $encodingAesKey, $Corpid)
    {
        $this->m_sToken = $token;
        $this->m_sEncodingAesKey = $encodingAesKey;
        $this->m_sCorpid = $Corpid;
    }

    /*
	*验证URL
    *@param sMsgSignature: 签名串，对应URL参数的msg_signature
    *@param sTimeStamp: 时间戳，对应URL参数的timestamp
    *@param sNonce: 随机串，对应URL参数的nonce
    *@param sEchoStr: 随机串，对应URL参数的echostr
    *@param sReplyEchoStr: 解密之后的echostr，当return返回0时有效
    *@return：成功0，失败返回对应的错误码
	*/
    public function VerifyURL($sMsgSignature, $sTimeStamp, $sNonce, $sEchoStr, &$sReplyEchoStr)
    {
        if (strlen($this->m_sEncodingAesKey) != 43) {
            return ErrorCode::$IllegalAesKey;
        }

        $pc = new Prpcrypt();
        //verify msg_signature
        $sha1 = new SHA1();
        $ret = $sha1->getSHA1($this->m_sToken, $sTimeStamp, $sNonce, $sEchoStr);

        if ($ret == null) {
            return -40003;
        }

        $signature = $ret;
        if ($signature != $sMsgSignature) {
            return ErrorCode::$ValidateSignatureError;
        }

        $result = $pc->decrypt_qyh(base64_decode($this->m_sEncodingAesKey . "="), $sEchoStr, $this->m_sCorpid);
        if ($result[0] != 0) {
            return $result[0];
        }
        $sReplyEchoStr = $result[1];

        return ErrorCode::$OK;
    }
    /**
     * 将公众平台回复用户的消息加密打包.
     * <ol>
     *    <li>对要发送的消息进行AES-CBC加密</li>
     *    <li>生成安全签名</li>
     *    <li>将消息密文和安全签名打包成xml格式</li>
     * </ol>
     *
     * @param $replyMsg string 公众平台待回复用户的消息，xml格式的字符串
     * @param $timeStamp string 时间戳，可以自己生成，也可以用URL参数的timestamp
     * @param $nonce string 随机串，可以自己生成，也可以用URL参数的nonce
     * @param &$encryptMsg string 加密后的可以直接回复用户的密文，包括msg_signature, timestamp, nonce, encrypt的xml格式的字符串,
     *                      当return返回0时有效
     *
     * @return int 成功0，失败返回对应的错误码
     */
    public function EncryptMsg($sReplyMsg, $sTimeStamp, $sNonce, &$sEncryptMsg)
    {
        $pc = new Prpcrypt();

        //加密
        $array = $pc->encrypt_qyh(base64_decode($this->m_sEncodingAesKey . "="), $sReplyMsg, $this->m_sCorpid);
        $ret = $array[0];
        if ($ret != 0) {
            return $ret;
        }

        if ($sTimeStamp == null) {
            $sTimeStamp = time();
        }
        $encrypt = $array[1];

        //生成安全签名
        $sha1 = new SHA1;
        $ret = $sha1->getSHA1($this->m_sToken, $sTimeStamp, $sNonce, $encrypt);

        if ($ret == null) {
            return -40003;
        }

        $signature = $ret;

        //生成发送的xml
        $xmlparse = new XMLParse;
        $sEncryptMsg = $xmlparse->generate($encrypt, $signature, $sTimeStamp, $sNonce);
        return ErrorCode::$OK;
    }


    /**
     * 检验消息的真实性，并且获取解密后的明文.
     * <ol>
     *    <li>利用收到的密文生成安全签名，进行签名验证</li>
     *    <li>若验证通过，则提取xml中的加密消息</li>
     *    <li>对消息进行解密</li>
     * </ol>
     *
     * @param $msgSignature string 签名串，对应URL参数的msg_signature
     * @param $timestamp string 时间戳 对应URL参数的timestamp
     * @param $nonce string 随机串，对应URL参数的nonce
     * @param $postData string 密文，对应POST请求的数据
     * @param &$msg string 解密后的原文，当return返回0时有效
     * @param $type string 默认是 json
     *
     * @return int 成功0，失败返回对应的错误码
     */
    public function DecryptMsg($sMsgSignature, $sTimeStamp = null, $sNonce, $sPostData, &$sMsg, $type = 'json')
    {
        if (strlen($this->m_sEncodingAesKey) != 43) {
            return ErrorCode::$IllegalAesKey;
        }

        $pc = new Prpcrypt();

        if ($sTimeStamp == null) {
            $sTimeStamp = time();
        }

        if ($type == 'json') {
            //提取密文
            $data = json_decode ( $sPostData);
            $encrypt = $data->Encrypt;
            $touser_name = $data->ToUserName;
        } else {
            //提取密文
            $xmlparse = new XMLParse;
            $array = $xmlparse->extract($sPostData);
            $ret = $array[0];
            if ($ret != 0) {
                return $ret;
            }
            $encrypt = $array[1];
            $touser_name = $array[2];
        }


        //验证安全签名
        $sha1 = new SHA1;
        $ret = $sha1->getSHA1($this->m_sToken, $sTimeStamp, $sNonce, $encrypt);

        if ($ret == null) {
            return -40003;
        }

        $signature = $ret;
        if ($signature != $sMsgSignature) {
            return ErrorCode::$ValidateSignatureError;
        }

        $result = $pc->decrypt_qyh(base64_decode($this->m_sEncodingAesKey . "="), $encrypt, $this->m_sCorpid);
        if ($result[0] != 0) {
            return $result[0];
        }
        $sMsg = $result[1];

        return ErrorCode::$OK;
    }
}